Key takeaways

• P60–P80 is commonly used for initial body filler shaping, not final prep.
• P120–P180 helps remove coarse filler scratches before moving finer.
• P240–P320 is commonly used before primer, depending on the repair and primer system.
• P400–P600 is a common final primer prep range before many basecoat systems, but the coating TDS should decide the final grit.
• P1500–P3000 is normally clear coat correction territory, not filler or primer shaping territory.
• The safest grit is the grit that removes the previous scratch pattern without creating a deeper problem for the next stage.

Download the SPX automotive sanding grit chart PDF

Use this as the printable version for the prep bay. It should sit near the sanding discs, not buried in a folder on someone’s desktop.

Download the SPX Automotive Sanding Grit Chart PDF

What grit should I use? Quick answer by job

Here is the fast answer. The deeper explanations follow below.

Quick automotive sandpaper grit chart

This chart is a practical starting point for automotive refinishing. Paint systems, primer build, substrate, colour, film thickness, curing conditions and the product technical data sheet still decide the final process.

Choose your sanding grit by job

Use these quick selectors like a workshop decision guide. They can be built as HTML accordion blocks on the live page.

Grit-by-grit explanation

Grit choice is not about memorising one magic number. It is about knowing what each grit is good at, and what it will wreck if you use it in the wrong place.

What grit sandpaper should you use for body filler?

Use P60–P80 for initial body filler shaping, then refine through P120–P180 before moving toward P240–P320 for final surfacing.

Body filler, or bog as plenty of Australian shops still call it, needs enough cut to level the repair before the surface gets polished smooth. Start too fine and you skate over high spots. Stay too coarse for too long and you carve marks that take extra primer and extra time to bury.

For DA filler shaping, use SPX 150mm ceramic sanding discs in P60–P80. For refinement, move into SPX 150mm ceramic discs from P120 and finer. On flat panels, keep a block in the process. A DA can make a repair look better than it is.

What grit should you use before primer?

Before primer, most filler repairs should be refined beyond coarse shaping scratches. Many workflows move through P180, P240 and P320 depending on the repair and primer system.

Primer surfacer can fill minor sanding marks. It should not be treated like a bin for bad prep. If deep P80 scratches are still sitting in the repair, primer can cover them at first, then shrink-back makes the shortcut visible later.

• Small repair: P80 shape, P120/P180 refine, P240/P320 before primer.
• Large repair: Use guide coat and block work to confirm shape before committing to primer.
• Unknown coating: Clean, inspect and follow the coating system’s TDS before sanding aggressively.

What grit should you use for primer surfacer?

Primer surfacer is commonly sanded around P320–P600, depending on whether you are blocking for straightness, preparing for sealer, or finishing for basecoat.

Early primer blocking needs enough bite to flatten texture and reveal lows. Final primer prep needs a controlled scratch pattern so the topcoat has adhesion without deep marks showing through.

For cleaner primer sanding on a DA, use a well-matched 15-hole disc, backing pad and dust extraction setup. SPX stocks sanding discs, 150mm base plates and 150mm interface pads for different sanding stages.

What grit should you sand before painting a car?

For many basecoat and clearcoat systems, final sanding often sits around P400–P600, with finer choices depending on the paint system, colour, substrate, sealer use and manufacturer instructions.

This is where bad internet advice gets expensive. A solid colour, metallic basecoat, sealer process, plastic bumper, spot repair and full respray can all need different prep. Do not treat one number as universal.

What grit should you use to wet sand clear coat?

Clear coat correction usually starts much finer than primer or filler work. For many modern clear coats, P1500–P2000 is a safer starting range, then refinement through P3000 helps reduce compounding time.

Clear coat has very little tolerance for rough sanding. P1000 or P1200 can have a place on heavy texture, runs or experienced correction work, but it is aggressive compared with P1500 and P2000. If you do not know the clear thickness, stay conservative.

For this stage, SPX 150mm sponge-back wet/dry discs in P1000–P4000 suit denibbing, orange peel correction and pre-polish refinement work. The sponge backing helps with contour control, but it does not replace judgement.

Scratch pattern comparison

The grit number matters because each grit leaves a scratch pattern the next stage must remove. If the next grit cannot remove the previous scratches, the defect gets buried until primer, basecoat or clear makes it visible again.

SPX recommended workflow by repair type

These are practical workflow examples. They are not a replacement for the paint system TDS, but they show how a shop can think through grit progression.

Small filler repair on a door

1. Shape cured filler with P80.
2. Refine with P120.
3. Remove coarse scratches with P180.
4. Feather edge with P240.
5. Final surface with P320 where suitable for the primer.
6. Prime, guide coat and block.
7. Final prep primer with P400–P600 depending on the system.

Primer surfacer block sanding

1. Apply guide coat.
2. Block with P320 or P400 to check shape.
3. Address lows before moving finer.
4. Refine with P500 or P600 for many basecoat systems.
5. Clean properly before masking and paint.

Clear coat orange peel correction

1. Confirm the clear has cured enough for correction.
2. Inspect film build where possible.
3. Mask or avoid sharp edges.
4. Test spot with P1500 or P2000.
5. Refine with P3000.
6. Compound, polish and inspect under proper light.

Dust nib removal

1. Let the clear cure as required.
2. Target the nib locally with P2000 or P3000 where suitable.
3. Keep the water clean.
4. Polish the small correction area, then inspect from multiple angles.

Bumper curve or soft panel

1. Use an interface pad or softer backing where the shape needs it.
2. Reduce pressure.
3. Avoid aggressive sanding on edges and body lines.
4. Check the scratch pattern often. Curved plastic hides mistakes until paint.

Sanding problem diagnosis chart

People search grit charts before the job. They search troubleshooting after something has gone wrong. Keep this chart close when the finish starts telling on the prep.

Wet sanding vs dry sanding: when to use each

Dry sanding is common for filler, primer and fast material removal. Wet sanding is mainly used for fine finishing, clear coat correction and high-grit refinement.

Do not wet sand filler as a shortcut. Filler and moisture are a bad mix, and water hiding in repairs before primer can create problems you do not see straight away.

For dusty stages, use extraction and suitable respiratory protection. SPX carries P2 dust masks, but spray painting, solvent work, isocyanate materials and hazardous dusts can require higher-level controls and properly selected respiratory protective equipment.

DA sanding vs hand sanding: which is better?

A DA sander is faster and more consistent for many stages, but hand sanding and block sanding are still better when straightness, edge control or tight access matters.

A DA is a production tool. A block is a truth tool. Good prep usually uses both.

Common bad sanding advice

Bad grit advice sounds simple. That is why it spreads. The panel does not care how confident the advice sounded.

Recommended SPX abrasive setup by job stage

This is where the chart becomes useful for ordering. Keep the right grit stages in stock so the prep team is not forced to improvise with whatever is left in the drawer.

FAQ: automotive sandpaper grit chart

What grit sandpaper should I use for car paint?

For repainting over prepared primer or existing coating, many systems use a final prep range around P400–P600. Blend areas and some paint systems may require finer preparation. Always check the paint manufacturer’s TDS.

What grit sandpaper should I use before primer?

Many filler repairs move through P80 for shaping, P120–P180 for refinement and P240–P320 before primer. The exact final grit depends on the primer system and repair type.

What grit do you use to sand body filler?

Use P60–P80 for initial body filler shaping, then refine through P120–P180. Move toward P240–P320 before primer where the primer system allows it.

What grit should I use before base coat?

P400–P600 is common for many primer prep workflows before basecoat, but the correct grit depends on the coating system, substrate, sealer use and colour.

Can I paint over 400 grit?

In some systems, yes. P400 can be suitable before certain primers, sealers or topcoat processes. It is not universal. Use the TDS for the coating being sprayed.

Is 600 grit good before paint?

P600 is commonly used for final primer prep before basecoat in many refinishing workflows. The surface still needs to be clean, stable and compatible with the paint system.

What grit should I wet sand clear coat with?

For many clear coat correction jobs, P1500–P2000 is a conservative starting range. Refine through P3000 before compounding and polishing.

What grit removes orange peel?

Light orange peel may be corrected with P2000 and refined with P3000. Moderate peel often starts around P1500. Heavy peel may require more aggressive correction, but only when film build and defect severity justify it.

Should I wet sand or dry sand primer?

Many panel shops dry sand primer because it works well with guide coat and dust extraction. Some systems allow wet sanding. Use the method recommended by the primer and paint manufacturer.

What happens if I skip sanding grits?

The next grit may not fully remove the previous scratch pattern. Those deeper scratches can show through primer, basecoat or clear, especially after the job cures and settles.

Sources and TDS note

This guide is based on practical abrasive progression used in automotive refinishing, SPX product suitability, coating manufacturer guidance and Australian workplace safety expectations.

Important: Always confirm final sanding recommendations against the paint, primer, filler or clear coat manufacturer’s technical data sheet. Grit selection can change depending on coating chemistry, colour, sealer use, film build, substrate, curing conditions and whether the job is a repair, blend or full refinish.

For workplace safety, check current Australian WHS guidance, the relevant product SDS and your shop’s respiratory protection process. Dry sanding painted surfaces, primers and fillers can create harmful dust. Spray painting and sanding some coatings may involve hazards that need more than a basic dust mask.

Related SPX guides and product pages

• Best 150mm Sanding Discs for Automotive Refinishing in Australia
• What Causes Sanding Pigtails?
• Understand Abrasive Cut Rates for Efficient Refinishing
• Paint Defect Removal Process Guide
• Sanding Discs
• Ironhead Abrasives
• Sanding Blocks
• Sanding Rolls
• Sanding Sheets
• Polishing Pads
• Masking Tape
• Safety Gear
• Request a Trade Account

Sources and technical data sheet note

This guide is designed as a practical sanding grit resource for Australian automotive refinishing work. It should sit beside, not replace, the technical data sheets for the filler, primer, sealer, basecoat, clear coat and polishing system being used.

Always confirm final sanding recommendations against the product manufacturer’s technical data sheet. Grit selection can change depending on coating chemistry, film build, colour, substrate, curing time, sealer use, temperature and the repair process.

For safety, also check the relevant safety data sheet and workplace requirements before sanding, spraying, cutting, polishing or working around airborne dust. Automotive refinishing can involve fine dust, solvents, isocyanates and other hazards that need the correct PPE and controls.